Magnetic sensor with limited element width

Abstract

A magnetic sensor is provided. The magnetic sensor includes a magneto-resistance element. The magneto-resistance element includes an anti-ferromagnetic layer, a fixed magnetic layer being in contact with the anti-ferromagnetic layer, and a free magnetic layer. The free magnetic layer opposes the fixed magnetic layer via a non-magnetic layer interposed therebetween. The free magnetic layer has a magnetization direction that varies in accordance with an external magnetic field. The magneto-resistance element has a narrow and longitudinal shape and has an element length L greater than an element width W that is in the range of about 1 μm to 5 μm.

1 . A magnetic sensor comprising a magneto-resistance element, the magneto-resistance element comprising; 
 an anti-ferromagnetic layer,    a fixed magnetic layer being in contact with the anti-ferromagnetic layer, and    a free magnetic layer opposing to the fixed magnetic layer via a non-magnetic layer interposed therebetween, the free magnetic layer has a magnetization direction that varies in accordance with an external magnetic field, and    wherein the magneto-resistance element has a narrow and longitudinal shape and has an element length L greater than an element width W that is in the range of about 1 μm to 5 μm.    
     
     
         2 . The magnetic sensor according to  claim 1 , wherein the element length L is about 50 μm to 250 μm.  
     
     
         3 . The magnetic sensor according to  claim 1 , wherein the non-magnetic layer is formed of Cu and a thickness of the non-magnetic layer is about 17 Å to 19 Å.  
     
     
         4 . The magnetic sensor according to  claim 3 , further comprising a control unit that is operative to output a switching signal on the basis of a variation in output due to a variation in magnitude of the external magnetic field.  
     
     
         5 . The magnetic sensor according to  claim 1 , wherein the non-magnetic layer includes Cu and a thickness of the non-magnetic layer is about 19.5 Å to 21 Å.  
     
     
         6 . The magnetic sensor according to  claim 5 , further comprising a control unit that is operative to output a switching signal on the basis of a variation in output due to a polarity change of the external magnetic field.  
     
     
         7 . A magnetic sensor comprising a magneto-resistance element, the magneto-resistance element comprising; 
 an anti-ferromagnetic layer,    a fixed magnetic being in contact with the anti-ferromagnetic layer, and    a free magnetic layer that opposes the fixed magnetic layer via a non-magnetic layer interposed therebetween, free magnetic layer has a magnetization direction that varies with an external magnetic field, and    wherein an interlayer coupling magnetic field Hin acts between the fixed magnetic layer and the free magnetic layer has a greater strength than that of a coercive force Hc of the free layer.    
     
     
         8 . A magneto-resistance element comprising; 
 an anti-ferromagnetic layer,    a fixed magnetic that is in contact with the anti-ferromagnetic layer,    a free magnetic layer that opposes the fixed magnetic layer, and    a non-magnetic layer interposed free magnetic layer and the fixed magnetic,    wherein the free magnetic layer has a magnetization direction that varies with an external magnetic field, and    wherein an interlayer coupling magnetic field operably acts between the fixed magnetic layer and the free magnetic layer, the interlayer coupling magnetic field having a greater strength than that of a coercive force of the free layer.